Monday, February 08, 2016

Magnesium levels in hospitalized patients: hyper may be worse than hypo

All admissions to
Mayo Clinic in Rochester, Minnesota, from January 1, 2009, through
December 31, 2013 (288,120 patients), were screened. Admission Mg
from each unique patient and relevant clinical data were extracted
from the institutional electronic database.

Results

After excluding
patients aged less than 18 years, those without Mg measurement, and
readmission episodes, a total of 65,974 patients were studied.
Magnesium levels of 2.1 mg/dL or higher were found in 20,777 patients
(31.5%), and levels less than 1.7 mg/dL were noted in 13,320 (20.2%).
Hypomagnesemia was common in patients with hematologic/oncological
disorders, and hypermagnesemia was common in those with
cardiovascular disease. The lowest hospital mortality, assessed by
restricted cubic spline and percentage death, occurred in patients
with Mg levels between 1.7 and 1.89 mg/dL. An Mg level of less than
1.7 mg/dL was independently associated with an increased risk of
hospital mortality after adjusting for all variables except the
admission diagnosis; risk for longer hospital stay and being
discharged to a care facility were increased in the fully adjusted
model. An elevated Mg level of 2.3 mg/dL or higher was a predictor
for all adverse outcomes. The magnitude of Mg elevations in patients
with levels of 2.3 mg/dL or higher (N=7908) was associated with worse
hospital mortality in a dose-response manner. In patients with
cardiovascular diseases, Mg levels of 1.5 to 1.69 mg/dL and 2.3 mg/dL
or higher both independently predicted poor outcomes including
hospital mortality.

Conclusion

Dysmagnesemia in
hospitalized patients is common, with hypermagnesemia being most
prevalent. Compared with hypomagnesemia, hypermagnesemia is a
stronger predictor for poor outcomes. Magnesium supplementation for
patients without Mg deficiency should be avoided in the absence of
randomized controlled trials documenting a benefit.